The present invention relates generally to a novel construction of a head positioner or alignment device useful with a cephalometric x-ray, or similar type of imaging machine, which which improves upon the head positioning devices of the prior art.
Cephalometric x-ray machines, and similar imaging devices, have become quite popular in modern medical applications. Orthodontics especially, for example, has derived significant benefits from utilization of cephalometric x-ray machines. Images or x-rays produced by these machines provide orthodontists and other professionals with a valuable diagnostic tool in their practice because these machines can produce stationary, planar images, and can produce images that are panoramic in nature. Thus, cephalometric x-ray machines present a diagnostic tool that is desired by many orthodontists.
Because of the ability of the cephalometric x-ray to provide both stationary and panoramic images of a patient, it is necessary that the head be positioned precisely prior to imaging and that this precise position be maintained throughout the entire imaging process. Accordingly, a head positioner is provided with many cephalometric x-ray units. Unfortunately, however, the head positioners of the prior art have a number of shortcomings, which leave room for improvement in several respects.
The head positioners must precisely position a patient's head, and maintain that precise positioning throughout an imaging session. To do this, some means must be provided engagable with the patient's head. Ear pieces are a common embodiment of the last-mentioned means. In the prior art, some of these ear pieces are slidably or pivotally arranged to slide or pivot laterally away from one or both sides to allow initial insertion of the patient's head therebetween, and then slide or pivot laterally inwardly to engage and position the head. These ear pieces are often spring-loaded to facilitate their pivotal movements. However, the pivoting of the ear pieces under the influence of the springs may injure the patient's head. This is undesirable. Sliding ear pieces may move outwardly only to the extent permitted by a film holder to one side, and hence, only the ear piece on the side opposite the film holder is usually moved outwardly appreciably. This also implies independent positioning of the ear pieces. With such independently positionable ear pieces, it is difficult to accurately center the patient's head.
Additionally, the ear pieces must be capable of variable separating movement with respect to each other to accommodate heads of various sizes. In order to overcome the foregoing problems, some prior art devices have employed arrangements for simultaneously symmetrically adjusting the ear pieces. These prior art positioners effected this symmetrical separating movement by a relatively complex and expensive rack and pinion-type mechanism. The cost and complexity of this mechanism often renders these positioners too expensive and too complicated for some practitioners, and also difficult and expensive to service and to repair.
Furthermore, many of the prior art positioners are wall mounted units. These wall mounted units require utilization of an adjustable patient chair in order to place the patient at an appropriate height relative to the positioner for imaging. The cost of a height-adjustable chair adds to the overall cost of employing the cephalometric x-ray unit, making it economically out of reach of some practitioners.
An additional problem with these wall mounted head positioners is that they have mounting plates which allow for mounting of the units on a wall on twelve inch centers. Because the standard wall stud placement distance is every sixteen inches along a wall, the prior art devices have to be anchored, at least in part, solely by the material of the wall itself. Due to the weight of the units, they may pull the anchors out of the wall under the influence of gravity and the forces inherent in adjusting the positioner for each patient. This causes alignment problems during imaging, to say nothing of the resultant damage to the wall.
Self-contained, pedestal mounted units which provide all of the necessary height and head positioning adjustments are also available. However, such units are extremely expensive as compared to wall mounted equipment.
The head positioner, constructed according to the teachings of the present invention, is intended to assist in solving these, as well as other problems present in head positioners of the prior art.